Ten-year-old Dugan Smith was diagnosed with a rare kind of cancer in his thigh bone, leaving him with a softball-sized tumor. Usually, similar patients have their legs partially amputated and are given cadaver or prosthetic thigh bones. But Dugan wanted to keep playing baseball.

Instead, his doctors took out a chunk of his thigh, rotated his lower leg 180 degrees, and reattached it. Yes: He has a backwards leg. But even more amazing than that: His ankle is now, essentially, his knee, thanks to the way the doctors attached the tendons and nerves, and with the aid of a prosthetic, he can still play baseball. Honestly, it's kind of hard to explain, because it seems so weird, so watch the video. Medicine! Science! The future! This kid is going to be a hit at college parties.